Thin film transistor liquid crystal displays are developing more and more rapidly and have become mainstream flat panel displays. From the time they came out up to the present, multiple categories of thin film transistor liquid crystal displays have been developed, driving modes and display effects thereof are different, and each category has its own advantages. Among them, a thin film transistor liquid crystal display in an In-Plane Switching (IPS) mode (comprising an array substrate in the IPS mode) exhibits excellent display capability and effect with its unique structural characteristics and driving principle.
As shown in FIG. 1, which is a plane view of an array substrate in the IPS mode, specific gaps 7 for avoiding short-circuit faults are provided between a pixel electrode 1 and a common electrode 2 when seen from the normal direction of the surface of the array substrate.
FIGS. 2a-2c are section views of an array substrate along the line I-I′ in FIG. 1 in continuous manufacturing steps thereof in the prior art. As shown in FIGS. 2a-2c, firstly, a first organic film 4 as shown in FIG. 2b is formed on the surface of a passivation layer 3 as shown in FIG. 2a, and then a strip-shaped pixel electrode 1 and a strip-shaped common electrode 2, which are arranged alternately as shown in FIG. 2c, are formed on the surface of the first organic film 4. Since the pixel electrode 1 and the common electrode 2 are arranged on the same plane of the array substrate, the aperture ratio of the array substrate is small and thus the light transmittance is low in the display process.
FIGS. 3a-3d are section views of an array substrate along the line I-I′ in FIG. 1 in another series of continuous manufacturing steps in the prior art. As shown in FIGS. 3a-3d, firstly, a strip-shaped pixel electrode 1 as shown in FIG. 3b is formed on the surface of a passivation layer 3 as shown in FIG. 3a, and then a first organic film 4 as shown in FIG. 3c covering the pixel electrode 1 is formed, and a strip-shaped common electrode 2 as shown in FIG. 3d is formed on the surface of the first organic film 4. In the manufacturing method, the pixel electrode 1 and the common electrode 2 are arranged on different planes of the same array substrate, so the transmittance can be increased, but the pixel electrode 1 and the common electrode 2 are formed in different processes. According to the above manufacturing steps, when the common electrode 2 is formed, the pixel electrode 1 has already been covered by the first organic film 4, and the common electrode 2 cannot be formed with the position of the pixel electrode 1 as a reference, so an error may occur on the specific gaps between the pixel electrode 1 and the common electrode 2 to thereby result in low precision of overlapping of the pixel electrode 1 and the common electrode 2 with respective preset positions.
To sum up, currently there is no array substrate capable of simultaneously achieving a high transmittance and overcoming the defect of the low precision of overlapping of the pixel electrode and the common electrode with respective preset positions.